Light hydrocarbons (e.g., natural gas) are abundant in North America. In 2010, the U.S. Energy Information Administration (EIA) estimated the U.S. light hydrocarbon reserves to be about 317 trillion cubic feet. Recent developments in light hydrocarbon production have made light hydrocarbons more economical as an energy source than other petroleum oil products (e.g., gasoline, diesel fuel). Moreover, light hydrocarbons are environmentally cleaner than other petroleum fuels because light hydrocarbons produce fewer greenhouse gases (e.g., carbon dioxide, methane).
For use as a fuel, light hydrocarbons may be cooled below their boiling point temperature to form liquefied light hydrocarbons (LLH). For example, the boiling point of non-compressed methane is about −164° C. or −263° F. at atmospheric pressure. Prior art attempts to deal with various challenges related to using a LLH fuel for vehicles powered by an internal combustion engine, such as the following: 1) insulating the LLH fuel from ambient heat; 2) vaporizing the LLH fuel before it enters a combustion chamber of the internal combustion engine; 3) providing enough LLH fuel to the internal combustion engine for sudden surges in demand for power (e.g., acceleration, high speeds, heavy loads); 4) avoiding excessive pressure-build-up inside the fuel tank from evaporation of the LLH fuel; and 5) minimizing emissions of greenhouse gases, especially vapor LLH fuel into the atmosphere when the vehicle is idle.
U.S. Pat. No. 5,373,700 describes a system for storing liquefied natural gas (LNG) and delivering vaporized LNG to an internal combustion engine. The system comprises an LNG fuel tank, a plurality of heat exchangers and gas regulator valves to maintain and control pressure inside the LNG fuel tank.
U.S. Pat. No. 5,884,488 describes a high-pressure LNG fuel system comprising an LNG fuel tank with a plurality of chambers, a cryogenic pump and an engine coolant-heated vaporizer to deliver vaporized LNG fuel to an internal combustion engine at about 3000 psig.
U.S. Pat. No. 6,698,211 describes a high-pressure LNG fuel system comprising a fuel tank, a pump and a vaporizer to deliver vaporized LNG fuel to the engine injectors at about 500 to about 3000 psig.
U.S. Pat. No. 6,058,713 describes a high-pressure LNG fuel system comprising a high-pressure fuel tank and a vaporizer using a high-pressure fuel tank to store the LNG at about 150 psi to about 1100 psi and to deliver the vaporized LNG fuel to the engine injectors at an adequate pressure.
The fuel systems described above tend to be complex, heavy, and difficult to maintain and require specialized components and materials to withstand cryogenic temperatures (e.g., cryogenic pumps, regulator valves, evaporators).
Thus, a LLH fuel system and method is needed that would be simple, light-weight, easy to maintain and utilize predominately standard components and materials.